Steve and Dick and Bill:
We had had PacBell's DSL (and a hub/router for our 3 Mac LAN) for some time, before I installed X for the first time.
I was in a brief panic when, in the Network System Pref panel, PPPoE was grayed-out and unavailable, after inserting/selecting
Built-in Ethernet and
Using DHCP in "the blanks".
One of the marvels of X (for me) is that everything else fell promptly into place, without further attention, while PPPoE remained "unavailable".
PacBell's "need" for PPPoE was somehow taken care of by the set-up, according to The Tortoise, who, at the time, reassured me it was nothing to be concerned about.
I don't think 9, which works seamlessly behind X in our 24-hour "on" set-up, makes any difference.
At least that's how it works out here . . .